Posted
by
timothy
on Monday September 13, 2010 @01:03AM
from the don't-cross-the-streams dept.

angry tapir writes "Researchers at Fujitsu Laboratories have developed a wireless charging system that they say can simultaneously charge a variety of portable gadgets over a distance of several centimeters without the need for cables. The system, which will be detailed at a technical conference in Japan this week, could begin appearing in mobile phones and other products as soon as 2012, the company said. Fujitsu's system is based on magnetic resonance in which power can be wirelessly sent between two coils that are tuned to resonate at the same frequency."

There definitely needs to be a set standard. I suspect IEEE or another such organization will eventually step up and figure out an agreeable standard.

However, the technology hasn't advanced to the point where it's exactly realistic for most people, or even truly usable. Unless there is a significant breakthrough in the near future, such standardization will probably not happen anytime soon.

I actually saw one of their demonstrations and it was cool. The pad was just a slightly thick mousepad like device, and you could put multiple phones of different types on it at the same time and at any orientation. They had modified battery modules to contain their own chip which did the inductive pick up and regulation. They said their goal was to get the chip built into devices by default, although unless the chip was very cheap, I suspect this would have been difficult to include in cost sensitive mobile phones and iPods.

This is a well-trodden area-- explored by many folks, starting with Tesla. Unfortunately there are several very basic phisical showbunglers if not showstoppers.Issues that are fundamental to electromagnetic radiation:

(1) If you send out EM waves, the efficiency of the antennas is like 1% at low frequencies, wasting 99.99% of the power. If you use microwave frequencies, the antennas are much more efficient, but so is your body's ability to absorb the stuff, which is not a good thing.

(2) If you try this near-field coupled resonator thing (first tried in 1886), you son find out it has very limited range, and you need coils as large as the distance to be spanned, and the power drops off as the square of the distance when near, as the cube of the distance a little bit farther away.

These are basic Maxwell's equation impediments that are unlikely to ever be overcome.

I modded you up, then thought about it for a sec. I think they're talking about using evanescent waves [wikipedia.org] instead of classical mutual inductance. Evanescent waves separate the near field and far field [wikipedia.org] when modeling antennas, btw.